approximately vs close to

approximately and close to both are adverbs.

Word	Noun	Adjective	Verb	Adverb
approximately	No	No	No	Yes
close to	No	No	No	Yes

As adverbs, approximately and close to are synonyms defined as:

approximately and close to: (of quantities) imprecise but fairly close to correct

Other synonyms of approximately include about, around, just about, more or less, or so, roughly, some.

approximately (adverb)	close to (adverb)
(of quantities) imprecise but fairly close to correct	(of quantities) imprecise but fairly close to correct